Cow protection is recommended in the Vedic literature because it is giving the most valuable foodstuff, milk.

680504SB.BOS                 Lectures
 Guest (4): What I... I was going to ask you, Swami, if the sacred cow was a symbol symbolizing compassion for all living creatures?
Prabhupada: Not only cow. Any animal, they should be object of our compassion. If we want to eat something and live, so if you have got sufficient foodstuff in other kingdom... We have got vegetables, we have got grains, we have got milk. So many things. Fruit, flower. So many things. Just like we are living on these things. We don't feel any inconvenience. And they are... According to medical science also, they are very rich in vitamins, food value. So why should we kill? Especially if we are human being, the cow is supplying us milk, the most important foodstuff. So instead of giving protection to the cow, if we kill, do you think that is very..., if you kill me, is that very good gratitude? So at least in the human life, these senses should be there. Cow protection is recommended in the Vedic  literature because it is giving the most valuable foodstuff, milk. Apart from other sentiments, it is supplying, and in exchange of nothing. She simply eats some grasses from the ground. That's all. You don't have to provide cows with foodstuff. The things which you refuse, you take the grain and you supply the skin. You take the fruit pulp, you supply the skin. You take the, I mean to say, from paddy. You take the rice. You supply the straw and she delivers you a very nice foodstuff. And I have discussed all these points in my Srimad-Bhagavatam, that human economic problem can be solved simply by having some land and some cows. That's all.